BYOB support for Fetch

Category: Network / Connectivity
Type: Chromium catches up
Status: Enabled by default (Chrome 116)
Intent stage: None

Breaking change: No
Enterprise impact: None
Chromium flag: ReadableStreamTeeCloneForBranch2 and FetchBYOB
Spec maturity: Published standard
Web Platform Tests: Yes

WPT details: https://wpt.fyi/results/fetch/api/response/response-consume-stream.any.html?label=experimental&label=master&aligned

Summary

Makes Response.body be a readable byte stream instead of a "default" readable stream. This enables it to be used with bring-your-own-buffer (BYOB) readers, reducing garbage collection overhead and copies.

Standards & signals

Specification: https://fetch.spec.whatwg.org/#http-network-fetch
Firefox: Shipped/Shipping — Already shipped in Firefox in 2022.
Safari: Support — @annevk said this looks good to WebKit, and they are supportive.
Web developers: No signals
Tracking bug: https://bugs.chromium.org/p/chromium/issues/detail?id=1243329

Ecosystem

Web Platform Tests: https://wpt.fyi/results/?q=fetch%2Fapi%2Fresponse%2Fresponse-consume-stream
Chrome Platform Showcase: https://chrome-platform-showcase.paulkinlan-ea.deno.net/features
GenDN reference: https://gendn.paulkinlan-ea.deno.net/features
chrome.dev demos search: https://www.google.com/search?q=site%3Achrome.dev+BYOB%20support%20for%20Fetch
MDN Web Docs: https://developer.mozilla.org/en-US/search?q=BYOB%20support%20for%20Fetch
Baseline status: https://webstatus.dev/?q=BYOB%20support%20for%20Fetch

View on chromestatus.com